The present invention relates to methods and systems for image processing and, more particularly, to a method and system for producing a composite image by combining a foreground image with a background image. Further, the present invention generally relates to a photobooth system and, more particularly, to a software operating system for a photobooth.
One of the most common methods of forming a composite image of a subject in the foreground of a pre-stored background image is the technique known as "chroma-key." As illustrated in FIGS. 1A-1C, the chroma-key technique typically involves the filming of a first image 24 (FIG. 1A) of the foreground subject 22 in front of a blue backdrop 25 and the subsequent image processing and superimposing of a pre-stored second image 27 (FIG. 1B) of a background 26 over all portions of the first image 24 having the particular color characteristics of the blue backdrop 25 to form a composite third image 28 (FIG. 1C) in which subject 22 appears in front of background 26. The chroma-key technique is currently widely employed in the movie industry, as well as in providing a television broadcast of a weatherman in front of satellite images and other weather maps.
Image processing systems used for chroma-key typically include a video camera or another form of image capturing device that optically filters the received optical image (24) using three different color filters. These three color filters are typically red, green, and blue, and are positioned between an imaging lens and a number of (usually 1 to 3) CCD sensor(s), or the like, such that red, green, and blue (RGB) analog video signals are generated. The RGB video signals represent the intensity of the RGB primary color components of the image 24. Conventional chroma-key devices receive these RGB video signals and compare the intensity of the blue, green, or red component or, in some cases, the relative intensity (or any other color corresponding to the backdrop 25) for each pixel (or point along an analog scan line) of the image 24 to a threshold intensity level (some devices look at the intensity or relative intensity and determine if it is in a range (i.e., between a minimum and maximum)). In most cases the RGB signal is converted to a different color space such as YUV or Y Cr Cb and comparisons are made with one or more of the components to determine the action of the chroma-key device. If the backdrop is saturated blue and the blue component intensity level of a pixel meets the criteria (range or threshold), the chroma-key device replaces that pixel with a pixel from a pre-stored background image 27 (i.e., such as a weather map). Some chroma-key devices mix the pixels of the foreground and background, the resultant pixel color components become a mathematical average (according to a predetermined algorithm) of the individual color components of the foreground pixel and the background pixel. The amount of each pixel's contribution to the resultant pixel is determined by the proximity of the intensity of one color component to a threshold intensity or range of intensities. The mixing method can be useful in some environments and the pixel replacement useful in others. It should be noted that there may be many different types of chroma-key devices available presently or to be developed in the future. For the purposes of this discussion, the term "pixel replacement" shall include mixing where the unwanted pixel is an unobjectable percentage of the resultant pixel. Thus, by utilizing a backdrop 25 that is a saturated blue color and illuminating it with light such that the reflected intensity as seen by the image capturing device is in the proper range such as that shown in FIG. 2A, the foreground subject 22 can be distinguished from the backdrop 25 in the RGB video signals so long as the foreground subject 22 is not wearing clothing that has a blue color component with a reflected intensity meeting the conditions for pixel replacement.
Chroma-key has been widely accepted in the movie and television environments primarily because of the ability to control the colors in the foreground subject's clothing or by controlling the overall colors in the foreground subject 22 itself so as to include color components such as those shown in FIG. 2B while not including the same blue color components as provided in the blue backdrop 25 (i.e., not having a blue component resulting in pixel replacement). However, in some environments such as a photobooth, one may not have any control over the colors of the foreground subject 22. For example, if a photobooth was equipped with chroma-key and someone off-the-street having blue clothing that produces the RGB components shown in FIG. 2C were to have a picture taken, the person 22 would appear transparent since the chroma-key device would superimpose the background image 27 over the person's clothing. Thus, chroma-key has been considered unsuitable for use in a photobooth. The unsuitability of chroma-key in such photobooth applications has been explicitly recognized in U.S. Pat. No. 5,345,313 issued to Blank and U.S. Pat. No. 5,469,536 issued to Blank.
Because of the demand in the market for a photobooth that is capable of superimposing the image 24 of a person(s) entering the photobooth over a background image 27, which may be an image of a famous tourist attraction, there exists the need for a method for providing an acceptable composite image 28 regardless of the colors of the foreground subject 22 entering the booth.
In an attempt to avoid the problems associated with utilizing a chroma-key technique in a photobooth, a technique is disclosed in U.S. Pat. No. 5,469,536 issued to Blank, which utilizes interactive digital editing techniques. This technique relies on digitally determining the edges of the subject image and assumes that the portion of the image lying between two consecutive edges is all subject (i.e., not to be subject to pixel replacement). This method, however, suffers from the difficulty in determining the edges of a subject if the edges or a portion of the edges are blue (or near in color to the background).
Presently, conventional photobooths are capable of performing only a few different types of image processing techniques such as providing a basic photograph or performing a processing technique known as "morphing" whereby images of two people are obtained and image processing is performed to provide an image of what a child of these two people might look like. Alternatively, an image of a single person may be obtained by the camera and subsequently "morphed" with the pre-stored image of a celebrity. To implement this morphing technique, which has only recently become high in demand, manufacturers of photobooths are having to totally replace their photobooths with new ones that specifically have this capability. However, if the demand for this morphing technique proves to just be a fad, and some new processing technique should subsequently become high in demand, photobooth manufacturers would again have to replace their photobooths with new photobooths to meet the demand for the new picture type. Because of the quickly changing trends in the art of the design and development of photobooths, there exists the need for a photobooth having a photobooth operating system and a versatile input mechanism that allows new functionalities to be implemented in the photobooth merely by writing a computer program within the parameters established by the photobooth operating system and adding the program to the system in a modular fashion.
Because photobooths are often installed in various wide-spread locations and are maintained by a single entity, there exists the need for a photobooth that is low in maintenance and rarely gets hung-up (caused by software lockups, power surges, etc.). Further, there exists the need for a photobooth that allows for the operator to perform diagnostic operations remotely over a telephone line or the like.